Shroud for space heater

ABSTRACT

A shroud is used to encompass a space heater ordinarily used within a tent or shelter. The shroud allows the space heater to be used outside the tent or shelter. 
     The shroud is made from a series of components and is readily disassembled to allow compactness for storage or moving. The shroud is positioned over the space heater and ambient air is drawn into the spaces between the shroud and the heater where the air is heated by the heater. The heated air leaves the shroud through a duct when extends to the tent or shelter sought to be heated.

INTRODUCTION

This invention relates to a shroud for a space heater and, more particularly, to a shroud for a space heater which will allow use outside a shelter for such a heater which heater is normally used inside a shelter when the shroud is not in place.

BACKGROUND OF THE INVENTION

Diesel or fuel powered space heaters are generally used in applications where power is unavailable. Fuel is delivered to the burner of such space heaters usually via gravity and the fuel so delivered is ignited manually. Following ignition, the space heater provides heat to the shelter.

A vent or draft is provided to allow air within the shelter to enter the burner combustion area of the heater. This air is combined with fuel and combusts within the burner thereby heating the casing of the heater. The combustion air is exhausted through a stack in the shelter and the non-combustion air within the shelter is heated by radiation from the casing of the heater. The heater works quite satisfactorily with various sizes being available for larger or smaller shelters.

One type of heater used in the military is known as the SHA heater. The SHA heater was designed by International Thermal Research Ltd. of Richmond, British Columbia, Canada. The acronym SHA stands for Space Heater, Arctic. The SHA heater is constructed to utilise fuels including diesel, kerosene, and jet fuel. When such fuels are not available, wood may be used. The heater is located inside the shelter. There are many hundreds of SHA heaters in use, principally by the military.

Although the SHA heater is designed to be used safely inside a shelter, it has been suggested that an outside location would also be useful. This is so since if the heater was located outside the tent, considerable space within the tent or shelter otherwise occupied by the heater could be reclaimed and used for other purposes. In addition, it is always possible to accidentally dislodge the heater and overturn it. Although the SHA heater is designed to provide only a small amount of free fuel if the heater is overturned, even a small amount of spilled fuel from a hot heater can be hazardous and result in a fire.

However, if the SHA heater is located outside the tent, the heat generated by the combusted fuel will dissipate into the atmosphere without reaching the interior of the tent or shelter. This is, of course, disadvantageous particularly in low temperatures.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a shroud for a space heater used for combusting fuel with the combustion products exiting the heater through a stack and combustion air entering the heater through a heater intake, a casing surrounding the heater which casing is heated by combustion within the heater and which casing radiates heat to the atmosphere, said shroud enclosing a significant portion of said space heater and allowing ambient air to circulate between said casing of said space heater and the inside of said shroud and to therefore become heated ambient air, an exit port formed in one end of said shroud to allow said heated ambient air to exit said shroud and to enter into a duct operable to extend to a tent or shelter and to discharge said heated ambient air into said tent or shelter, said shroud being removably positioned on said heater for facilitated installation or removal thereof, said shroud further having a door which may open or close to allow the commencement of combustion within said heater.

According to a further aspect of the invention, there is provided a method of heating a tent or shelter from a location outside said tent or shelter and using a space heater otherwise operable within said tent or shelter, said method comprising positioning said space heater outside said tent or shelter, positioning a removable shroud on said space heater such that said shroud substantially encloses said space heater and leaves air passageways between the outside of said space heater and the inside of said shroud, allowing said ambient outside air to enter said air passageway and to be heated by the outside of said space heater, directing said heated ambient air through a duct to said tent or shelter and releasing said heated ambient air into said tent or shelter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A specific embodiment of the invention will now be described, by way of example only, with the use of drawings in which:

FIG. 1 is a diagrammatic isometric view of the shroud positioned on the space heater and further illustrating the bottom or lower holding tray, all according to the invention;

FIG. 2 is a diagrammatic isometric view of the shroud positioned on the space heater but particularly illustrating the ambient and heated air exit port located on one side of the shroud according to the invention;

FIG. 3 is a diagrammatic exploded isometric view illustrating the construction and position of the shroud on the space heater and, as well, the position of the space heater within the bottom holding tray, according to the invention;

FIG. 4 is a diagrammatic side partial sectional view of the shroud in operable position on the space heater and particularly illustrating the ambient air flow between the shroud and the space heater and the discharge of the heated ambient air according to the invention;

FIG. 5 is a diagrammatic isometric view of the insulation layer installed on the top member of the shroud;

FIG. 6 is a diagrammatic side view of the duct extending from the shroud to the shelter with a fan installed within the duct;

FIG. 7A is a diagrammatic isometric view illustrating the shroud in its collapsed and transportable condition; and

FIG. 7B is a diagrammatic isometric bottom view of the shroud components in their collapsed and transportable condition and particularly illustrating the bottom of the lower tray.

DESCRIPTION OF SPECIFIC EMBODIMENT

Referring now to the drawings, a space heater is generally illustrated at 100 in FIGS. 1 and 3. The space heater 100 illustrated and known as an SHA (space heater, Arctic) heater which is used by the military inside shelters and tents. It is a relatively small, light weight and safe diesel-fueled non-powered heater. The heater 100 includes a carburetor 101 which regulates diesel flow to the burner (not illustrated), a door 102 mounted on vertical hinges which can be swung open and the space filled with wood if diesel fuel is unavailable or not preferred, a removable closure member (not illustrated) which is removably connected to the cutout 103 in the space heater 100 and which can be opened to allow primer fuel to be added to the burner when lighting the heater takes place and which closure member also includes a small glass viewing port (not illustrated) for observing the condition of the combustion flame and an outlet port 104 for exhausting the combustion products from the heater 100. A small metal cup 110 is wire connected to the carburetor 101 of the heater 100 and is used for priming the heater 100 with diesel fuel when combustion within the heater 100 is initiated.

The shroud is generally illustrated at 111 and comprises four side pieces 112, 113, 114, 115 and a top member 120 as best seen in FIG. 3. The four side pieces 112, 113, 114, 115 are all removably connected using open cutouts such as those shown at 121 in FIG. 3 and which allow the entry of corresponding locatable pressed out tabs such as tab 122 also illustrated in FIG. 3. The two ends of the side pieces 113, 114 hang from the top member 120 using the pressed tabs 123 (only one of which is shown) which enter into the corresponding cutouts or recesses 121 on side the panels 113, 114. The remaining side panels 112, 115 are retained by the sides of the top member 120 and the corresponding entry of tabs 122 into cutout 121 as illustrated more clearly in FIG. 1. The use of individual pieces for the shroud 111 allows for easier storage and convenience of transportation of the shroud 111.

The top member 120 has a series of cylindrical spacers 124 (FIG. 4) which are welded to the inner surface of the top member 120 and rest on the upper surface of the heater 100. Thus, an upper space which defines a longitudinal passageway 125 is formed between the inner surface of top member 120 and the upper surface of the heater 100. Likewise, the side members 112, 113, 114, 115 are designed to hang from the top member 120 at a distance from the sides and ends of the heater 100 when attached to the top member 120. They likewise form side and end passageways similar to the passageway 125 between the top member 120 and the space heater 100. The purpose of these passageways will be described in greater detail hereafter.

The top member 120 also has a door 130 which hinges about an interior connection (not shown) which allows the door 130 to be raised or lowered. A handle 132 is provided for carrying the collapsed shroud case 153 (FIG. 7A) and also allows a user to operate the door 130 when the heater 100 is in operation and to protect the hand of the user.

The top member 120 also has a hole 133 through which a stack 134 can extend. Stack 134 extends through the hole 133 and into the outlet port 104 (FIG. 3) of the space heater 100 so that the combustion products can be exhausted to the outside of the tent or shelter in which the heater 100 is located.

A bottom tray 140 has a pair of feet 141 which are hingedly mounted to the bottom tray 140 about axes 150. The feet 141 extend from the bottom of the bottom tray 140 to isolate the hot bottom tray 140 from the surface upon which the heater 100 and shroud 111 are positioned and to separate the heater 100 from the ground surface. The feet 141 may be folded upwardly about axes 150 as viewed in the figures when the heater 100 and shroud 111 are being stored or transported.

As best seen in FIG. 3, the bottom tray 140 allows the heater 100 is be securely mounted within the tray 140 when under operation. A fuel line (not illustrated) extends from the carburetor 101 to the burner (not illustrated) of the heater 100. A groove 142 therefore extends through the bottom tray 140 to allow passage of the fuel line. The bottom tray 140 also includes slots 152 (FIG. 7B) to allow for drainage and to allow for the passage of combustion air.

A shroud outlet 143 is cut through the end piece 113 and a collar 144 is welded to the shroud outlet 143. The collar 144 is intended to be connected to a removable duct 155 (FIG. 6) which can be removably connected to the collar 144. The duct 155 conveys heat leaving the shroud 111 to the shelter or tent 160 as will be further described.

Operation

In operation, it will be assumed that the heater 100 is no longer intended to be used within the tent or shelter 160 and that, instead, the heater 100 is intended to be used outside the tent or shelter 160 with the heat conducted from the heater 100 to the tent or shelter 160.

The tray 140 will have its feet or legs 141 rotated about axes 150 to the position illustrated in FIG. 1. The heater 100 will then be positioned with its bottom portion within the bottom tray 140 with the fuel tube (not illustrated) fitting securely within the groove 142. The top member 120 will be lowered onto the heater 100 until the spacers 124 contact the upper surface of the heater 100 as best seen in FIG. 4. The end members 113, 114 will be hung from the tabs 123 extending inwardly of the top member 120 by allowing the tabs 123 to enter the recesses or cutouts 121 on the end members 113, 114. The two end members 113, 114 will then hang from top member 120.

The upper portion of the side members 112, 115 will be positioned between the inside surface of the top member 120 and the outside surface of the heater 100. The recesses or cutouts 121 on each side will be inserted over the tabs 122 and allowed to move downwardly until there is a secure connection between the tabs 122 and the recesses or cutouts 121.

A duct 155 (FIG. 6) is mounted on to the collar 144 and will extend to the tent or shelter 160 which is intended to be warmed by the hot air heated by the heater 100. The heated air leaves the shroud 111 via the shroud outlet 143 and through the duct 155. The stack 134 is inserted through the hole 133 and is connected with the outlet port 104 of the heater 100. The stack 134 extends upwardly a predetermined distance from the outlet port 104 and the shroud hole 133.

The door 130 of the top member 120 of the shroud 111 is opened and the closure member 103 of the space heater 100 is removed to allow access to the inside of the heater 100 and, more particularly, to the burner (not illustrated) within the heater 100. The carburetor 101 is opened to allow fuel to run from the carburetor 101 to the burner and the metal cup 110 is filled with primer diesel which is then dumped into the heater 100 through the open door 130 and the open closure member 103. A piece of paper is lit and as it flames, it is dropped into the heater 100 through the open door 130 and open closure member 103 directly onto the raw diesel fuel previously placed in the burner of the heater 100. The closure member 103 and the door 130 are then each closed, respectively.

The diesel fuel will light from the burning paper and operation of the heater 100 will then commence. Ambient air will enter the heater 100 through the louvers 151 supplying combustion air to the heater 100. The combustion will generate heat within the heater 100 which will generally provide radiation type heat emanating from around the outside of the heater 100 with the combustion products leaving the heater 100 through the stack 134.

Referring to FIG. 4, cool inlet ambient air enters the shroud 111 around the bottoms of each of the side members 112, 113, 114, 115. The radiation heat being given off by the heater 100 will provide significant heat to the air passing within the five (5) longitudinal passageways formed between the heater 100 and shroud 111. The heated air will exit the shroud 111 through the shroud cutout 143 and collar 144 and will be conveyed by the duct 155 to the tent or shelter 160 sought to be heated.

It will be appreciated that the heater 100 and shroud 111 are used with shelters that may be transient and moved frequently. In this event, the side panels 112, 113, 114, 115 are readily removed from the top member 120, the stack 134 is readily removed from the outlet port 104 of the heater 111 and the duct extending from the collar 144 of the shroud 111 to the tent or shelter is likewise removed. The space heater 100 is removed from the bottom tray 140 and the legs 141 of the tray 140 are folded upwardly to form a compact package. The bottom tray 140 is set within the top member 120 and the several side pieces 112, 113, 114, 115 fit within. Thus, the package shown generally at 153 (FIGS. 7A and 7B) is in the form of a carrying case. The shroud 111, the stack 134 and the duct 155 may then be transported in a relatively small package to the next location where it may again be used for heating by assembling the components as has been described.

Many modifications will readily occur to those skilled in the art to which the invention relates. To provide a better draft for the ambient air entering the spaces 125 between the shroud 111 and the heater 100 as seen in FIG. 4, a fan 154 (FIG. 6) is used to draw ambient air more quickly through the spaces 125 by providing a lower pressure within the duct 155. The fan 154 could be powered by various power sources such as the wind, solar energy or by a thermal electron generator positioned on the heater 100.

Likewise, to reduce the wasted heat which might be given off by the shroud 111, it is contemplated that an insulating coat 156 (FIG. 5) made from an insulating material could be attached to the outer surface of the shroud 111 as by snap fasteners or the like. This insulating layer 156 would prevent heat emanating from the outer surface of the shroud 111 being wasted thereby increasing the efficiency of the heating operation to the duct.

Many further modifications will readily occur to those skilled in the art to which the invention relates and the present description is given by way of specific examples only which should not be taken as limiting the scope of the invention as defined in accordance with the accompanying claims. 

1. A shroud for a space heater used for combusting fuel with the combustion products exiting the heater through a stack and combustion air entering the heater through a heater intake, a casing surrounding the heater which casing is heated by combustion within the heater and which casing radiates heat to the atmosphere, said shroud enclosing a significant portion of said space heater and allowing ambient air to circulate between said casing of said space heater and the inside of said shroud and to therefore become heated ambient air, an exit port formed in one end of said shroud to allow said heated ambient air to exit said shroud and to enter into a duct operable to extend to a tent or shelter and to discharge said heated ambient air into said tent or shelter, said shroud being removably positioned on said heater for facilitated installation or removal thereof, said shroud further having a door which may open or close to allow the commencement of combustion within said heater.
 2. A shroud as in claim 1 wherein said shroud comprises a top member and four side members.
 3. A shroud as in claim 2 wherein said top member and said side members are individual components.
 4. A shroud as in claim 3 wherein at least one of said side members is removably connected to said top member and hangs downwardly from said top member.
 5. A shroud as in claim 4 wherein at least two of said side members are removably connected to said top member and hang downwardly from said top member.
 6. A shroud as in claim 5 wherein said side members number four (4), two of said side members hanging from said top member of said shroud and two of said side members being positioned inside said top member and being secured by said two side members hanging from said top member.
 7. A shroud as in claim 6 and further comprising a bottom tray operable to hold said heater.
 8. A shroud as in claim 7 wherein said bottom tray has movable legs which extend downwardly from said bottom tray and which are rotatable on said bottom tray.
 9. A shroud as in claim 8 and further comprising a cutout in one of said side members.
 10. A shroud as in claim 9 and further comprising a collar mounted to said cutout and a duct extending from said collar.
 11. A shroud as in claim 10 and further comprising a fan in said duct to draw air into said shroud and out from said cutout.
 12. A shroud as in claim 11 and further comprising a cutout in said top member operable to allow a stack to extend though said cutout to said heater.
 13. A shroud as in claim 12 and further comprising a door in said top member operable to be opened or closed to allow access though said shroud and into the interior of said heater.
 14. A method of heating a tent or shelter from a location outside said tent or shelter and using a space heater otherwise operable within said tent or shelter, said method comprising positioning said space heater outside said tent or shelter, positioning a removable shroud on said space heater such that said shroud substantially encloses said space heater and leaves air passageways between the outside of said space heater and the inside of said shroud, allowing said ambient outside air to enter said air passageway and to be heated by the outside of said space heater, directing said heated ambient air through a duct to said tent or shelter and releasing said heated ambient air into said tent or shelter.
 15. A method as in claim 14 and further comprising using a fan in said duct to draw said ambient outside air into said air passageway.
 16. A method as in claim 15 and further comprising inserting said space heater into a bottom tray, and extending a plurality of legs connected to said bottom tray thereby to allow the lower surface of said bottom tray to be positioned above the surface on which said legs are positioned.
 17. A method as in claim 16 wherein at least some of said side members are hung from said top member to allow spaces for said air passageway.
 18. A method as in claim 17 and further comprising exhausting the combustion products from said heater through a stack extending through said shroud.
 19. A method as in claim 18 and further comprising forming a door in said shroud and allowing said door to open or close thereby to allow access to said heater from outside said shroud. 